[0001] This invention relates to a polyphenylene ether resin composition. More particularly,
the present invention is concerned with a polyphenylene ether resin composition comprising
a polyphenylene ether resin and a rubber modified resin which composition is excellent
in resistance to aggressive solvents and colorability.
[0002] It is well known that polyphenylene ether resins are excellent in mechanical properties
and electrical properties such as electric insulation properties. Further, polyphenylene
ether resins are low in water absorption and have a good dimensional stability. In
addition to the above-mentioned excellent properties, it is noted that disadvantageous
properties of polyphenylene ether resins such as poor moldability and poor impact
strength have been successfully eliminated by blending them with a high impact polystyrene.
[0003] Therefore, in recent years, such polyphenylene ether resins have begun to be used
for a wide variety of applications.
[0004] However, both of polyphenylene ether resins and polyblends of polyphenylene ether
resins with a high impact polystyrene have a fatal drawback, namely poor resistance
to organic solvents such as acetone, hexane, cyclohexane and gasoline, machine oils
and grease. When polyphenylene ethers and polyblends thereof with a high impact polystyrene
are contacted with the above-mentioned substances, crazing is caused. Particulary,
their stress crack resistance is low.
[0005] That is, these resins easily fail by breaking when exposed to mechanical stress while
being in contact with the above-mentioned substances.
[0006] Meanwhile, as polyphenylene ether resins and resin com- positions comprising a polyphenylene
ether and a high impact polystyrene are widely used, it is strongly desired to give
them colors possessing various hues. However, those resins and resin compositions
are poor in colorability. Particularly, it is difficult to give them colors possessing
a vivid hue.
[0007] Heretofore, various proposals have been made to improve stress crack resistance of
polyphenylene ether resins and polyphenylene ether resin compositions. For example,
U.S. Patent Nos. 3,819,761 and 3,976,725 each propose the use of a high molecular
weight polystyrene; U.S. Patent No. 3,994,856 proposes the addition of A-B-A' type
elastomeric block copolymer; and U.S. Patent 4,167,507 proposes the.addition of a
hydrogenated block copolymer. However, by these expedients, not only a satisfactory
improvement with respect to stress crack resistance cannot be achieved but also mechanical
properties, e.g., rigidity are spoiled.
[0008] U.S. Patent 3,383,435 discloses a composition comprising a acrylonitrile-butadiene-styrene
copolymer (hereinafter often referred to as "ABS resin") and poly(2,6-dimethyl-l,4-phenylene)ether.
In example of U.S. Patent 3,383,435, composition samples are prepared from a polyphenylene
ether r
psin and an ABS resin comprising 16% acrylonitrile units, 41% styrene units, and 43%
butadiene units. However, as is apparent from the comparison, described in example
of U.S. Patent 3,383,435, of the properties of the resulting compositions with those
of a composition comprising a polyphenylene ether and a polystyrene or a composition
comprising a polyphenylene ether and a high impact polystyrene, the resulting compositions
are too brittle to use for practical purposes. This is attributable to a poor compatibility
between an ABS resin and a polyphenylene ether.
[0009] Meanwhile, as mentioned above, a polyphenylene ether resin and a polyblend of a polyphenylene
ether resin with a styrene resin are poor in colorability. Accordingly, improvement
of colorability of the above-mentioned resin or polyblend : has been desired in the
art. U.S. Patent No. 4,060,514 discloses a method of reducing the color of polyphenylene
ether.
[0010] But, heretofore, there have been made no proposals with respect to methods of improving
colorability of the resin composition comprising a polyphenylene ether resin and a
polystyrene.
[0011] The present inventors have made extensive and intensive studies on a resin composition
comprising a rubber modified resin and a polyphenylene ether resin, particularly on
a rubber modified resin containing a vinyl cyanide compound and the structure and
effect thereof. As a result, the present inventors have surprisingly found that a
resin composition comprising a polyphenylene ether resin and a specific rubber modified
resin containing a vinyl cyanide compound is excellent in not only impact strength
but also solvent resistance and colorability. The present invention has been made
based on such a novel finding.
[0012] The foregoing and other features and advantages of the present invention will be
apparent to those skilled in the art from the following detailed description and appended
claims.
[0013] According to the present invention, there is provided a polyphenylene ether resin
composition comprising:
(A) 10 to 80% by weight of a polyphenylene ether resin, and
(B) 90 to 20% by weight of a rubber modified resin, said rubber modified resin containing
a discontinuous elastomeric rubber phase dispersed in a continuous resin phase comprising
a copolymer of a vinyl cyanide compound and a vinyl aromatic compound or a mixture
of a homopolymer of a vinyl aromatic compound and a copolymer of a vinyl cyanide compound
and a vinyl aromatic compound, said elastomeric rubber phase comprising a grafted
elastomeric rubber which has a graft phase of a copolymer of a vinyl cyanide compound
and a vinyl aromatic compound, said elastomeric rubber phase having a grafting degree
of 20 to 300% by weighty said grafting degree is defined by the formula:
wherein G represents the grafting degree, % by weight;
R the amount of rubber contained in one gram of the rubber modified resin, gram; and
A the amount of the elastomeric rubber phase contained in one gram of the rubber modified
resin, gram,
said copolymer of a vinyl cyanide compound and a vinyl aromatic compound of the graft
phase having a moiety of the vinyl cyanide compound in an amount of 5 to 30% by weight
based on the total amount of the vinyl cyanide compound moiety and the vinyl aromatic
compound moiety present in the graft phase,
said copolymer of a vinyl cyanide compound and a vinyl aromatic compound of the continuous
resin phase having a moiety of the vinyl cyanide compound in an amount of 3 to 10%
by weight based on the amount of the continuous resin phase.
[0014] In a preferred composition of the present invention, the polyphenylene ether resin
as component(A) is a homopolymer comprising a repeating structural unit represented
by the formula(I) or a copolymer comprising a repeating structural unit represented
by the formulatI) and a repeating structural unit represented by the formula(II):
wherein R
l, R
2, R
3, R
4,R
5 and R
6 each independently represent a monovalent substituent selected from the group consisting
of an alkyl group having 1 to 4 carbon atoms excluding a tert-butyl group; an aryl
group; a halogen atom; and a hydrogen atom, provided that R
5 and R
6 do not simultaneously represent a hydrogen atom.
[0015] As illustrative examples of a homopolymer comprising a repeating structural unit
represented by the above formula(I), there may be mentioned poly(2,6-dimethyl-l,4-phenylene)ether,
poly(2-methyl-6-ethyl-1,4-phenylene)ether, poly(2,6-diethyl-1,4-phenylene)ether, poly(2-ethyl-6-n-propyl-l,4-phenylene)-ether,
poly(2,6-di-n-propyl-1,4-phenylene)ether, poly (2-methyl-6-n-butyl-1,4-phenylene)ether,
poly(2-ethyl-6-isopropyl-l,4-phenylene)ether, poly(2-methyl-6-chloro-1,4-phenylene)ether,
poly(2-methyl-6-hydroxyethyl-1,4-phenylene)-ether, poly(2-methyl-6-chloroethyl-1,4-phenylene)ether
and the like. Of the above-mentioned homopolymer type polyphenylene ethers, the most
preferred one for the purposes of the present invention is poly(2,6-dimethyl-1,4-phenylene)-ether.
[0016] The polyphenylene ether resin comprising a copolymer of a repeating structural unit
represented by the above formula (I) and a repeating structural unit represented by
the above formula (II) includes a polyphenylene ether copolymer produced by copolymerising
an alkyl-substituted phenol, such as 2,3,6-trimethylphenol, represented by the formula
(wherein R
3, R
4, R
5 and R
6 each are as defined above) with o-cresol or the like. Of the above-mentioned copolymer
type polyphenylene ether resins, the most preferred one for the purposes of the present
invention is a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol.
[0017] As mentioned above, the polyphenylene ether resin composition of the present invention
comprises a polyphenylene ether resin [component(A)] and a rubber modified resin
[component (B)]. Where the amount of the polyphenylene ether resin contained in the
polyphenylene ether resin composition is less than 10% by weight based on the components
(A) and (B), the heat resistance characteristic of the polyphenylene ether is spoiled
and, hence, such a composition cannot be put to practical use. On the other hand,
where the amount of the polyphenylene ether resin is more than 80% by weight based
on the components (A) and (B), the processability of the composition is drastically
lowered. Therefore, the amount of the polyphenylene ether resin contained in the composition
of the present invention should be within the range of 10 to 80% by weight based on
the components (A) and (B).
[0018] As mentioned above, the rubber modified resin as component (
B) of the polyphenylene ether resin composition of the present invention contains a
discontinuous elastomeric rubber phase dispersed in a continuous resin phase comprising
a copolymer of a vinyl cyanide compound and a vinyl aromatic compound or a mixture
of a homopolymer of a vinyl aromatic compound and a copolymer of a vinyl cyanide compound
and a vinyl aromatic compound. The elastomeric rubber phase comprises a grafted elastomeric
rubber which has a graft phase of a copolymer of a vinyl cyanide compound and a vinyl
aromatic compound. In a preferred composition of the present invention, the vinyl
aromatic compound as the monomer unit of the homopolymer and as one of the monomer
units constituting the copolymer is at least one member selected from the group of
compounds represented by the formula:
wherein R represents a hydrogen atom, a halogen atom or an alkyl group; Z a hydrogen
atom, a halogen atom, a vinyl group or an alkyl group; and p an integer of 1 to 5.
[0019] As more preferable vinyl aromatic compounds, there may be mentioned at least one
member selected from the group consisting of styrene, α-methylstyrene, vinyltoluene,
vinylethylbenzene, vinylxylene,tert-butylxylene and chlorostyrene. Of the above-mentioned
vinyl aromatic compounds, most preferred are styrene and a mixture of styrene and
α-methylstyrene. As the mixture of styrene and a-methylstyrene, a mixture of 20 to
80% weight of styrene and 80 to 20% by weight of d-methylstyrene is preferred.
[0020] The vinyl cyanide compound as one of the monomer units constituting the copolymer
in the rubber modified resin component is at least one member selected from the group
of compounds represented by the formula:
H
2C=CR'-C=N wherein R' represents a hydrogen atom or an alkyl group having 1 to 4 carbon
atoms.
[0021] As representative examples of the vinyl cyanide compounds represented by the above
formula, there may be mentioned at least one member selected from the group consisting
of acrylonitrile, methacrylonitrile, d-ethylacrylonitrile, d-propylacrylonitrile,
«-butylacrylonitrile and the like. Of the above-mentioned vinyl cyanide compounds,
at least one member selected from the group consisting of acrylonitrile and methacrylonitrile
is preferable and acrylonitrile is most preferable.
[0022] In the elastomeric rubber phase of the rubber modified resin, it is important that
in order to impart high impact strength, excellent solvent resistance and colorability
to the polyphenylene ether resin composition, not only the grafting degree (which
will be defined later) of the elastomeric rubber phase be within a specific range,
but also the respective contents of vinyl cyanide compound moiety in the graft phase
and resin phase be within specific ranges. Specifically, where the content of vinyl
cyanide compound moiety in the graft phase is less than 5% by weight based on the
total amount of the vinyl cyanide compound moiety and the vinyl aromatic compound
moiety present in the graft phase, the colorability and solvent resistance of the
polyphenylene ether resin composition are insufficient. On the other hand, where the
content of vinyl cyanide compound moiety in the graft phase is more than 30% by weight,
both the colorability and impact strength of the polyphenylene ether resin composition
are lowered. Accordingly, in the present invention, the content of vinyl cyanide compound
moiety in the graft phase is within the range of 5 to 30% by weight. Where the grafting
degree of the elastomeric rubber phase is less than 20% by weight, the colorability
and impact strength as well as solvent resistance of the polyphenylene ether resin
composition are poor. On the other hand, the upper limit of the grafting degree is
generally 300% by weight in view of the present techniques for attaining a high grafting
degree and from the standpoints of desired impact strength and processability of the
polyphenylene ether resin composition. In the preferred composition of the present
invention, the graft phase of the grafted elastomeric rubber phase in the rubber modified
resin comprises two classes of copolymers, namely, (a) a copolymer of a vinyl cyanide
compound and a vinyl aromatic compound containing a moiety of the vinyl cyanide compound
in an amount of 3 to 15% by weight based on the copolymer and (b) a copolymer of a
vinyl cyanide compound and a vinyl aromatic compound containing a moiety of the vinyl
cyanide compound in an amount of 16 to 40% by weight based on the copolymer, the average
content of vinyl aromatic compound moiety in the two classes of copolymers being 5
to 30% by weight based on the total amount of the copolymers present in the graft
phase. In such a graft phase, it is preferred that the two classes of copolymers have
a weight ratio (a)/(b) of 9/1 to 1/9, more preferably 4/1 to 1/4. Where the elastomeric
rubber phase in the rubber modified resin comprises a grafted elastomeric rubber which
has the graft phase comprising the above-mentioned two classes of copolymers, the
polyphenylene ether resin composition of the present invention is extremely excellent
in both of impact strength and solvent resistance.
[0023] As mentioned above, with respect to the continuous resin phase in the rubber modified
resin, it is requisite that the copolymer of a vinyl cyanide compound and a vinyl
aromatic compound in the continuous resin phase have a moiety of the vinyl cyanide
compound in an amount of 3 to 10% by weight based on the amount of the continuous
resin phase. Where the content of the vinyl cyanide compound in the resin phase is
less than 3% by weight, the colorability and solvent resistance of the polyphenylene
ether resin composition is lowered. On the other hand, where the content of the vinyl
cyanide compound in the resin phase exceeds 10% by weight, the impact strength of
the polyphenylene ether resin composition is remarkably lowered. In the present invention,
the rubber moiety of the elastomeric rubber phase may be any polymeric materials which
are elastic. The term "rubber" as used in the present invention, therefore, includes,
natural or synthetic rubbers of the diene elastomer type, copolymers of such dienes
with other monomers, and other homopolymers and copolymers which are elastic. Illustrative
examples of the rubber as mentioned above include a polybutadiene, a styrene-butadiene
copolymer, a butadiene-acrylonitrile copolymer, a styrene-butadiene block copolymer,
a hydrogenated product of the styrene-butadiene block copolymer, an ethylene=propylene-ethylidene
norbornene terpolymer, an ethylene-propylene-dicyclopentadiene terpolymer, a polyalkyl
acrylate, a polyisoprene, a natural rubber and the like. The rubber moiety of the
elastomeric rubber phase may be at least one member selected from the group consisting
of the above-mentioned rubbers. Of the above-mentioned rubbers, preferred is at least
one member selected from the group consisting of a polybutadiene, a styrene-butadiene
copolymer,an ethylene-propylene-ethylidene norbornene terpolymer and an ethylene-propylene-dicyclopentadiene
terpolymer. The amount of rubber moiety of the elastomeric rubber phase may be within
the range of 1 to 25% by weight based on the total amount of components(A) and (B).
The suitable amount of the rubber moiety may be chosen from the above-mentioned range
according to the intended impact strength of the polyphenylene ether resin composition.
[0024] The method for the production of a rubber modified resin as component(B) is not critical
as far as the resulting rubber modified resin meet the above-mentioned requirements
with respect to the grafting degree and the vinyl cyanide conpound moiety content
of each of the graft phase and resin phase. For example, the rubber modified resin
may be prepared by a generally known polymerization technique such as emulsion, bulk,
solution or suspension polymerization. Further, the rubber modified resin may be produced
by the following method. Copolymerization of a vinyl cyanide compound with a vinyl
aromatic compound is carried out in the presence of a rubber to form a rubber grafted
with a copolymer of a vinyl cyanide compound and a vinyl aromatic compound. Separately,
a vinyl cyanide compound and a vinyl aromatic compound are copolymerized to form a
diluting resin. Subsequently, the obtained grafted rubber and diluting resin are mixed
with each other to form a rubber modified resin. With respect to this method, a more
specifical explanation will be given later.
[0025] With respect to the analysis of rubber modified resins, there are various methods,
e.g. methods as described in J. Polymer Sci., A3, 3825 (1965), and Rubber Chem. &
Technology, 38, No. 3, 655 (1965). In the present invention, the fractionation of
discontinuous elastomeric rubber phase and continuous resin phase, and the determination
of the grafting degree of the elastomeric rubber phase were made according to the
following method. One gram of the rubber modified resin is added to 25 ml of methyl
ethyl ketone. The resulting suspension is sufficiently shaked and is centrifuged at
20,000 rpm at 0°C to separate the suspension into a precipitate and a supernatant
solution. The resulting supernatant solution contains the resin phase. The resin phase
is recovered from the supernatant solution by means of precipitation with methanol.
The precipitate obtained by centrifugation is recovered as the elastomeric rubber
phase. The term "grafting degree" as used in the present invention is defined by the
following formula:
wherein G represents the grafting degree, % by weight;
R the amount of rubber contained in one gram of the rubber modified resin, gram; and
A the amount of the elastomeric rubber phase contained in one gram of the rubber modified
resin, gram.
[0026] The content of the vinyl cyanide compound moiety in each of the resin phase and elastomeric
rubber phase is determined by the elementary analysis method.
[0027] When the graft phase comprises two classes of copolymers, namely, a copolymer containing
a moiety of the vinyl cyanide compound in an amount of 3 to 15% by weight based on
the copolymer and a copolymer containing a moiety of the vinyl cyanide compound in
an amount of 16 to 40% by weight based on the copolymer, fractionation of the graft
phase is carried out as follows. The graft phase is recovered from the above- separated
elastomsric rubber phase by the method known as "oxidation destruction method of rubber".
In'this method, the rubber moiety of the elastomeric rubber phase is decomposed using
osmium tetraoxide and hydroperoxide. The fractionation of the recovered graft phase
can be made by generally known various methods, for example, by the column fractionation
method as described in "Polymer Sci., Polymer Physics Edition, Vol. 19, 1377(1981)".
In the present invention, there is used the following convenient method for fractionation
of the graft phase. The obtained graft phase is added to a mixed solvent of acetone
and methanol. The resulting suspension is sufficiently shaked and, then, centrifuged
to separate insoluble matters from the suspension. In this connection, the proportion
of acetone to methanol of the mixed solvent is appropriately adjusted prior to the
use for the fractionation of the graft phase. For example, a mixture of acetone and
methanol (7/3 by volume) can be advantageously used for fractionation of the graft
phase because a copolymer containing the vinyl cyanide compound moiety in an amount
of 15% or less by weight based on the copolymer is insoluble in the mixed solvent
while a copolymer containing the vinyl cyanide compound moiety in an amount of 16%
or more by weight based on the copolymer is soluble in the mixed solvent. After the
fractionation, the content of the vinyl cyanide compound moiety in each of the separated
copolymers is determined by the elementary analysis method.
[0028] The grafting degree of the elastomeric rubber phase and the vinyl cyanide compound
moiety content of each of the resin phase and graft phase may be determined either
by analyzing the rubber modified resin prior to the blending of the rubber modified
resin with the polyphenylene ether resin or by analyzing the prepared polyphenylene
ether resin composition bacause there is no difference in the data obtained between
these two cases.
[0029] The polyphenylene ether resin composition of the present invention may additionally
contain high impact polystyrenes, various styrene-butadiene block copolymers in an
appropriate amount as far as the excellent solvent resistance and colorability characteristic
of the polyphenylene ether resin composition of the present invention are not spoiled.
[0030] Further, other additives known to those skilled in the art may be present in the
polyphenylene ether resin composition of the present invention such as plasticizers;
stabilizers; ultraviolet absorbers; flame retardant additives; colorants; mold release
agents;.. fibrous reinforcing agent such as glass fibers and carbon fibers; and fillers
such as glass bead, calcium carbonate and talc. As preferred examples of the plasticizers,
there may be mentioned polybutenes, low molecular weight polyethylenes, mineral oils,
epoxidized soybean oils, polyethylene glycols, and fatty esters. As the stabilizers,
there may be mentioned phosphites, hindered phenols, alkanol amines, acid amides,
metal salts of dithio- carbamic acid, inorganic sulfides and metal oxides. They are
used alone or in combination.
[0031] The method of forming the polyphenylene ether resin composition is not critical.
That is, components (A) and (B) may be blended by generally known methods, for example,
by means of extruder, heated roll, Bunbury mixer, Kneader and the like.
[0032] The following Examples illustrate the present invention in more detail but should
not be construed as limiting the scope of the invention.
[0033] All parts used herein are by weight unless otherwise specified.
[0034] The properties shown herein are measured according to the following methods.
Falling weight impact strength
[0035] Measurement was done substantially in accordance with ASTM D1709-75 (Reapproved 1980)
except that as follows. Specimens: 150 mm x 150 mm x 2 mm flat plates formed by injection
molding of the composition at 290°C.
[0036] Test method: A semispheric missile having a radius of 1/2 in. and having a certain
weight is allowed to drop from a height of 150 cm onto the middle of a specimen. When
the specimen fails, the missile weight is decreased by 100 grams and is allowed to
drop from the same height as mentioned above onto another specimen. When the specimen
does not fail, the missile weight is increased by 100 grams and is allowed to drop
from the same height as mentioned above onto the specimen. The above-mentioned tests
are repeated to determine the missile weight which would result in 50% failure of
specimens tested.
[0037] The falling weight impact strength is calculated by the following equation:
I(kg.cm) = 150(cm) x W(gram) wherein I represents the falling weight impact strength
and W the missile weight which would result in 50% failure of specimens tested.
Solvent resistance
[0038] A type-I dumbbell test piece according to ASTM D638 which has been formed by injection
molding at 280°C is immersed in cyclohexane at 23°C for 24 hours and taken out of
cyclohexane. After 10 minutes, the test piece is weighed. Solvent resistance is expressed
by cyclohexane absorption calculated by the following equation:
wherein W
l represents the weight of test piece before immersion, gram; and W
2 the weight of test piece after immersion, gram.
[0039] Also, the test piece is examined with respect to occurence of cracking after immersion.
Colorability
[0040] Two groups of standard samples are prepared as follows. As one group of standard
samples, black standard samples are prepared by adding various amounts of carbon black
° (particle diameter: 200A) as indicated below to 100 parts by weight of resin mixtures
consisting of 40 parts by weight of poly(2,6-dimethyl-l,4-phenylene)ether having an
intrinsic viscosity [η] of 0.62 (as measured at 30°C in chloroform) and 60 parts by
weight of a high impact polystyrene comprising 10% by weight of a polybutadiene rubber
(weight mean particle diameter: 3.0 µ) and 90% by weight of a polystyrene and classified
into ranks as indicated below.
[0041] As the other group of standard samples, white standard samples are prepared by adding
various amounts of TiO
2 (particle diameter: 2000A) as indicated below to 100 parts by weight of resin mixtures
consisting of 40 parts by weight of poly(2,6-dimethyl-1,4-phenylene)ether having an
intrinsic viscosity [η] of 0.62 (as measured at 30°C in chloroform) and 60 parts by
weight of a high impact polystyrene comprising 10% by weight of a polybutadiene rubber
(weight mean particle diameter: 3.0 µ) and 90% by weight of a polystyrene and classified
into ranks as indicated below.
[0042] A black sample for estimation of colorability is prepared by adding 0.5 part by weight
of carbon black (particle diameter: 200A) to 100 parts by weight of a polyphenylene
ether resin composition. A white sample for estimation of colorability is prepared
by adding 3 parts by weight of Ti0
2 (particle diameter: 2000Å) to 100 parts by weight of a. polyphenylene ether resin
composition. Colorability is determined by the method in which the black sample and
white sample are compared with the black standard samples and white standard samples,
respectively and what ranks of black and white standard samples respectively corresponds
to the black and white samples are visually determined.
Standard Samples
(1) Black
[0043]
(2) White
[0044]
Production of a rubber modified resin
[0045] A representative method of producing a rubber modified resin will be described below.
(1) Preparation of a grafted rubber latex
[0046] .40 Parts by weight (on the solid basis) of a polybutadiene latex having a weight
mean particle diameter of 4500A and 100 parts by weight of water were charged into
a reactor and heated to 70°C in an atmosphere of gaseous nitrogen while stirring.
Then, a monomer phase containing 12 parts by weight of acrylonitrile, 48 parts by
weight of styrene and 0.1 part by weight of dodecyl mercaptan and a solution.prepared
by dissolving 0.2 part by weight of potassium persulfate in
50 parts by weight of water were separately, simultaneously added to the polybutadiene
latex over 5 hours. After completion of the addition, the reactor was further kept
at 70°C for 2 hours to complete polymerization. The conversion of monomers was 95%.
(2) Preparation of a diluting resin latex
[0047] 120 Parts by weight of water and 1.0 part by weight of potassium rosinate for disproportionation
were charged into a reactor and heated to 70°C in an atmosphere of gaseous nitrogen
while stirring. Then, a monomer phase containing 4 parts by weight of acrylonitrile,
96 parts by weight of styrene and 0.3 part by weight of dodecyl mercaptan and a solution
prepared by dissolving 0.2 part by weight of potassium persulfate in 50 parts by weight
of water were separately, simultaneously added over 7 hours. After completion of the
addition, the reactor was further kept at 70°C for 2 hours to complete polymerization.
The conversion of monomers was 94%.
(3) Preparation of a rubber modified resin
[0048] 50 Parts by weight (on the solid basis) of the above-prepared grafted rubber latex
and 50 parts by weight (on the solid basis) of the above-prepared diluting resin latex
were sufficiently mixed and dispersed each other. The resulting latex was subjected
to coagulation by adding 2.
0 parts by weight of aluminum sulfate, followed by filtration. The resulting cake was
washed with water and dried to obtain a rubber modified resin.
[0049] The obtained rubber modified resin was fractionated according to the above-mentioned
method and analyzed.
[0050] The results are as follows.
Adjustment of grafting degree and the content of vinyl cyanide compound moiety
[0051] In preparation of a grafted rubber, the grafting degree is usually adjusted by changing
the amount of dodecyl mercaptan to be added. The larger the amount of dodecyl mercaptan
to be added, the lower the grafting degree. The grafting degree can also be adjusted
by changing the amount ratio of rubber to monomers in polymerization or the period
of time in which a monomer phase and an aqueous potassium persulfate solution are
added to the reactor. The vinyl cyanide compound moiety content of the graft phase
is adjusted by changing the amount of the vinyl cyanide compound to be added in preparation
of a grafted rubber. The vinyl cyanide moiety content of the resin phase is adjusted
by changing the amount of the vinyl cyanide compound to be added in preparation of
a diluting resin, the ratio of a grafted rubber to a diluting resin and the like.
[0052] In the following Examples and Comparative Examples,t
he grafting degree and the vinyl cyanide compound moiety content of each of the graft
phase and resin phase of the rubber modified resin were adjusted as mentioned above.
,Examples 1 and Comparative Examples 1 and 2
[0053] First, rubber modified resins Nos. 1 to 3 shown in Table 1 were prepared in substantially
the same manner as described above with respect to the-representative method of producing
a rubber modified resin except that adjustments of the grafting degree of the elastomeric
rubber phase and the acrylonitrile moiety content (hereinafter frequently referred
to as "AN content") of each of the resin phase and graft phase were carried out in
the above-mentioned manner "Adjustment of grafting degree and the content of vinyl
cyanide compound moiety".
[0054] A polyphenylene ether resin composition was obtained by blending, by means of a blender,
40 parts by weight of poly(2,6-dimethyl-1,4-phenylene)ether having an intrinsic viscosity
[η] of 0.62 (as measured at 30°C in chloroform), 60 parts by weight of a rubber, modified
resin No. 1 consisting of a graft phase and a resin phase both shown in Table 1 and
containing 20% by weight of rubber, 0.5 part by weight of Sumilizer BHT (trade name
of hindered phenol manufactured and sold by Sumitomo Chemical Co. Ltd., Japan) as
a stabilizer and 0.5 part by weight of MARK PEP-8 (trade name of distearyl pentaerythritol
diphosphite.manufactured and sold by ADEKA ARGUS Chemical Co., Ltd., Japan ).
[0055] For comparison, a comparative polyphenylene ether resin composition'was obtained
in the same manner as mentioned above except that a rubber modified resin No. 2 consisting
of a graft phase and a resin phase both shown in Table 1 and containing 20% by weight
of rubber was used instead of the above-mentioned rubber modified resin No. 1.
[0056] Another comparative polyphenylene ether resin composition was obtained in the same
manner as described above except that a rubber modified resin No. 3 consisting of
a graft phase and a resin phase both shown in Table 1 and containing 20% by weight
of rubber was used instead of the above-mentioned rubber modified resin No. 1 or No.
2.
[0057] The above-obtained compositions were pelletized by means of an extruder at 300°C.
[0058] Falling weight impact strength, solvent resistance and colorability of the above-obtained
samples were measured. The results are shown in Table 2.
[0059] As seen from the results shown in Table 2, the composition of Comparative Example
1 not containing acrylonitrile moiety has a cyclohexane absorption as large as 0.27%
by weight. Further, many cracks were observed on the surface of the immersed dumbbell
test piece of Comparative Example 1. In the case where the cyclohexane absorption
is
0.
07% by weight or less (Examples 1 and Comparative Example 2), any cracks were not observed.
The composition of Comparative Example 2 having AN content of the graft phase as large
as 32% by weight is very poor in falling weight impact strength. On the other hand,
the composition of Example 1 is excellent in falling weight impact strength, solvent
resistance and colorability.
Example 2
[0060] A rubber modified resin was prepared as follows.
[0061] 20 Parts by weight (on the solid basis) of a polybutadiene ° latex having a weight
mean particle diameter of 4500A and 100 parts by weight of water were charged into
a reactor and heated to 70°C in an atmosphere of gaseous nitrogen while stirring.
Then, a monomer phase containing 5 parts by weight of acrylonitrile, 75 parts by weight
of styrene and 0.1 part by weight of dodecyl mercaptan and a solution prepared by
dissolving 0.3 part by weight of potassium persulfate in 50 parts by weight of water
were separately, simultaneously added to the polybutadiene latex over 7 hours. After
completion of the addition, the reactor was further kept at 70°C for 2 hours to complete
polymerization. The conversion of monomers was 95%.
[0062] The resulting polymer latex was subjected to coagulation by adding 2.0 parts by weight
of aluminum sulfate, followed by filtration. The resulting cake was washed with water
and dried to obtain a rubber modified resin.
[0063] The obtained rubber modified resin was analyzed according to the above-mentioned
method. The results are as follows.
[0064] A polyphenylene ether resin composition was obtained in the same manner as in Example
1 except that 60 parts by weight of the above-obtained rubber modified resin was used.
The thus prepared composition was pelletized by means of an extruder at 300°C.
[0065] Falling weight impact strength, solvent resistance and colorability of the above-obtained
sample were measured.
[0066] The results are as follows.
Examples 3 through 5
[0067] First, rubber modified resins Nos. 4 to 6 shown in Table 3 were prepared in substantially
the same manner as described above with respect to the representative method of producing
a rubber modified resin except that adjustments of the grafting degree of the elastomeric
rubber phase, and the acrylonitrile moiety content of each of the resin phase and
graft phase were carried out in the above-mentioned manner "Adjustment of grafting
degree and the content of vinyl cyanide compound moiety".
[0068] A polyphenylene ether resin composition was obtained by blending, 40 parts by weight
of poly(2,6-dimethyl-l,4-phenylene) ether having an intrinsic viscosity [q] of 0.62
(as measured at 30°C in chloroform), 60 parts by weight of a rubber modified resin
No.
4 consisting of a graft phase and a resin phase both shown in Table 3 and containing
25% by weight of rubber, 0.5 part by weight of Sumilizer BHT (trade name of hindered
phenol manufactured and sold by Sumitomo Chemical Co. Ltd., Japan) as a stabilizer
and 0.5 part by weight of MARK PEP-8 (trade name of distearyl pentaerythritol diphosphite
manufactured and sold by ADEKA ARGUS Chemical Co. Ltd., Japan)..
[0069] Another polyphenylene ether resin composition was obtained in the same manner as
described above except that a rubber modified resin No.
5 consisting of a graft phase and a resin phase both shown in Table 3 and containing
25
% by weight of rubber was used instead of the above-metnioned rubber modified resin
No. 4.
[0070] Still another polyphenylene ether resin composition was obtained in the same manner
as described above except that a rubber modified resin No. 6 consisting of a graft
phase and a resin phase both shown in Table 3 and containing 25% by weight of rubber
was used instead of the above-mentioned rubber modified resin No. 4 or 5.
[0071] The above-obtained compositions were pelletized by means of an extruder at 300°C.
[0072] Falling weight impact strength, solvent resistance and colorability of the above-mentioned
samples were measured. The results are shown in Table 4.
[0073] As seen from Tables 3 and 4, the higher the grafting degree, the better is falling
weight impact strength,. solvent resistance and colorability.
Examples 6 and 7 and Comparative Example 3
[0074] First, rubber modified resins Nos. 7 to 9 shown in Table 5 were prepared in substantially
the same manner as described above with respect to the representative method of producing
a rubber modified resin except that adjustments of the grafting degree of the elastomeric
rubber phase, and the acrylonitrile moiety content of each of the resin phase and
graft phase were carried out in the above-mentioned manner "Adjustment of grafting
degree and the content of vinyl cyanide
compound moiety".
[0075] A polyphenylene ether resin composition was obtained by blending 50 parts by weight
of poly(2,6-dimethyl-1,4-phenylene)ether having an intrinsic viscosity [q] of 0.66
(as measured at 30°C in chloroform), 50 parts by weight of a rubber modified resin
No. 7 consisting of a graft phase and a resin phase both shown in Table 5 and containing
25% by weight of rubber, 0.5 part by weight of Sumilizer BHT (trade name of hindered
phenol manufactured and sold by Sumitomo Chemical Co. Ltd., Japan) as a stabilizer
and 0.5 part by weight of MARK PEP-8 (trade name of distearyl pentaerythritol diphosphite
manufactured and sold by ADEKA ARGUS Chemical Co. Ltd., Japan)
[0076] Another polyphenylene ether resin composition was obtained in the same manner as
described above except that a rubber modified resin No. 8 consisting of a graft phase
and a resin phase both shown in Table 5 and containing 25
% by weight of rubber was used instead of the above-mentioned rubber modified resin
No. 7.
[0077] For comparison, a comparative polyphenylene ether resin composition was obtained
in the same manner as described above except that a rubber modified resin No. 9 consisting
of a graft phase and a resin phase both shown in Table 5 and containing 25% by weight
of rubber was used instead of the above-mentioned rubber modified resin No. 7 or 8.
[0078] The above-obtained compositions were pelletized by means of an extruder at 300°C.
[0079] Falling weight impact strength, solvent resistance and colorability of the above-mentioned
samples were measured. The results are shown in Table 6.
[0080] As seen from Tables 5 and 6, the composition of Comparative Example 3 having an AN
content of resin phase of as large as 15% by weight is very poor in falling weight
impact strength and is very brittle as compared with the compositions of Examples
6 and 7.
Example 8
[0081] A rubber modified resin having a rubber content of 20% by weight as shown below was
prepared in substantially the same manner as described with respect to the representative
method of producing a rubber modified resin except that a mixture consisting of 57%
by weight of styrene and 43% by weight of α-methylstyrene was used instead of styrene
in the preparation of a grafted rubber and a diluting resin and that the adjustments
of the grafting degree and AN content of each of the resin phase and graft phase were
carried out in the above-mentioned manner "Adjustment of grafting degree and the content
of vinyl cyanide compound moiety".
Rubber modified resin
[0082]
[0083] A polyphenylene ether resin composition was obtained in the same manner as described
in Example 1 and Comparative Examples 1 and 2 except that the rubber modified resin
as obtained above was used instead of the rubber modified resin No. 1, 2 or 3.
[0084] The above-obtained composition was plelletized by means of an extruder at 300°C.
[0085] Falling weight impact strength, solvent resistance and colorability of the above-obtained
sample were measured. The results are as follows.
Example 9
[0086] A polyphenylene ether resin composition was obtained by blending 40 parts by weight
of a copolymer consisting of 90% by mole of 2,6-dimethylphenol and 10% by mole of
2,3,6-trimethylphenol and having an intrinsic viscosity [η] of 0.65 (as measured at
30°C in chloroform), 60 parts by weight of a rubber modified resin No.5 as mentioned
in Examples 3 through 5, 0.5 part by weight of Sumilizer BHT (trade name of hindered
phenol manufactured and sold by Sumitomo Chemical Co. Ltd., Japan) as a stabilizer
and 0.5 part by weight of MARK PEP-8 (trade name of distearyl pentaerythritol diphosphite
manufactured and sold by ADEKA ARGUS Chemical Co., Ltd., Japan).
[0087] The obtained composition was pelletized by means of an extruder at 300°C.
[0088] Falling weight impact strength, solvent resistance and colorability of the obtained
sample were measured. The results are as follows.
Example 10
[0089] A rubber modified resin having a rubber content of 20% by weight as shown below was
prepared in substantially the same manner as described with respect to the representative
method of producing a rubber modified resin except that methacrylonitrile was used
instead of acrylonitrile in the preparation of a grafted rubber and a diluting resin
and that the adjustments of the grafting degree and the methacrylonitrile moiety content
of the graft phase and resin phase were carried out in the above-mentioned manner
"Adjustment of grafting degree and content of vinyl cyanide compound moiety".
Rubber modified resin
[0090]
[0091] A polyphenylene ether resin composition was obtained in the same manner as described
in Example 1 and Comparative Examples 1 and 2 except that the rubber modified resin
as obtained above was used instead of the rubber modified resin No. 1, 2 or 3.
[0092] The above-obtained composition was pelletized by means of an extruder at 300°C.
[0093] Falling weight impact strength, solvent resistance and colorability of the above-obtained
sample were measured. The results are as follows.
[0094] The conditions for preparing rubber modified resin employed in Examples 1 to 10 and
Comparative Examples 1 to 3 as described before will be summarized in Table 7.
Example 11
[0095] A rubber modified resin having a high grafting degree was prepared by the bulk polymerization
method as will be described below.
[0096] 5 75 Parts by weight of styrene, 10 parts by weight of acrylonitrile, 15 parts by weight
of a polybutadiene rubber, 0.1 part by weight of benzoyl peroxide and 20 parts by
weight of ethylbenzene were charged into a reactor. The resulting mixture was kept,
while stirring, at 80°C for 5 hours, 130°C
10 for 3 hours and 150°C for 3 hours for polymerization reaction. The conversion of
monomers was 90%. After completion of the polymerization reaction, the reaction mixture
was allowed to stand at 230°C under a reduced pressure (5 mmHg) for 30 minutes to
remove ethylbenzene and unpolymerized monomers. Thus, a 15 grafted rubber was obtained.
[0097] A diluting resin latex was prepared in the same manner as in Examples 3 through 5.
100 Parts by weight (on the solid basis) of the above-prepared diluting resin latex
was subjected to coagulation by adding 2.0 parts by weight of aluminum 2
0 sulfate, followed by filtration. The resulting cake was washed with water and dried
to obtain a diluting resin.
[0098] 70 Parts by weight of the above-prepared grafted rubber and 30 parts by weight of
the above-prepared diluting resin and 0.2 part by weight of Sumilizer BHT as a stabilizer
were 25 blended and extruded by means of an extruder at 230°C to obtain a rubber modified
resin in a pelletized form.
[0099] The thus prepared rubber modified resin was analyzed according to the above-mentioned
analytical method. The results are as follows.
Rubber modified resin
[0100]
[0101] A polyphenylene ether resin composition was obtained in the same manner as in Example
1 except that 60 parts by weight of the above-prepared rubber modified resin was used.
The above-obtained composition was pelletized by means of an extruder at 300°C.
[0102] Falling weight impact strength, solvent resistance and colorability of the above-obtained
sample were measured. The results are as follows.
Example 12 and Comparative Example 4
[0103] A rubber modified resin of which the graft phase comprises two classes of copolymers
was prepared as follows.
[0104] 40 Parts by weight of polybutadiene latex having a weight average particle diameter
of 3500 A and 100 parts by weight of water were put into a reaction vessel and heated
to 70°C in an atmosphere of gaseous nitrogen while stirring. Then, a first monomer
phase containing 9 parts by weight of acrylonitrile, 21 parts by weight of styrene
and 0.1 part by weight of dodecyl mercaptan and an aqueous solution prepared by dissolving
0.1 part by weight of potassium persulfate in 50 parts by weight of water were separately,
simultaneously introduced into the reactor over 3 hours. Subsequently, a second monomer
phase containing 30 parts by weight of styrene and 0.1 part by weight of dodecyl mercaptan
and an aqueous solution prepared by dissolving 0.1 part by weight of potassium persulfate
in 50 parts by weight of water were separately, simultaneously introduced into the
reactor over 3 hours. After completion of the introduction, the mixture was further
maintained at a temperature of 70°C for 2 hours to complete polymerization. The conversion
of monomers was 93%.
[0105] The thus prepared rubber modified resin was analyzed according to the above-mentioned
analytical'.method.
[0106] The results are as follows.
[0107] The AN content of each of two classes of copolymers constituting the graft phase
was determined as follows.
[0108] The rubber moiety of the elastomeric rubber phase was decomposed using osmium tetraoxide
and hydroperoxide to recover the graft phase. 1 g of the obtained graft phase was
added to 25 ml of a mixed solvent of acetone and methanol (7/3 by volume) and dispersed
into the mixed solvent while shaking, whereby part of the graft phase was transferred
to the mixed solvent phase. The resulting dispersion was centrifuged to recover the
mixed solvent containing part of the graft phase from the dispersion. The AN content
of each of a graft phase soluble in the mixed solvent and a graft phase insoluble
in the mixed solvent was determined. The results are as follows.
[0109] Graft phase insoluble in the mixed solvent of acetone and methanol (7/3 by volume):
[0110]
Graft phase soluble in the mixed solvent of acetone and methanol (7/3 by volume):
[0111] For comparison, a conventionally known ABS resin (acrylonitrile-butadiene-styrene
resin) was prepared by the emulsion graft polymerization method as will be described
below.
[0112] 40 Parts by weight of a polybutadiene rubber and 100 parts by weight of water were
charged into a reactor and heated to 70°C. Then, a monomer phase containing 18 parts
by weight of acrylonitrile, 42 parts by weight of styrene and 0.2 part by weight of
dodecyl mercaptan and a solution prepared by dissolving 0.2 part by weight of potassium
persulfate in 50 parts by weight of water were separately, simultaneously introduced
into the reactor over 5 hours. After completion of the introduction, the reactor was
further kept at 70°C for 2 hours to complete polymerization. The conversion of monomers
was 93%. The resulting ABS resin latex was subjected to coagulation by adding 2.0
parts by weight of aluminum sulfate, followed by filtration. The resulting cake was
washed with water and dried to obtain an ABS resin. With respect to the resulting
ABS resin, the grafting degree of the elastomeric rubber phase, the AN content of
each of the graft phase and resin phase were determined in the same manner as mentioned
above. The results are as follows.
[0113]
Graft phase insoluble in the mixture of acetone and methanol (7/3 by volume):
[0114] Graft phase soluble in the mixture of acetone and methanol (7/3 by volume):
[0115] Subsequently, to 50 parts by weight of poly(2,6-dimethyl
- l,4-phenylene)ether having an intrinsic viscosity [η] of 0.62 (in chloroform at 30°C)
were added 50 parts by weight of the above-prepared rubber modified resin of which
the graft phase comprises two classes of copolymers and 0.5 part by weight of each
of Sumilizer BHT as a stabilizer and Mark PE
P-8, followed by blending using a blender to form a polyphenylene ether resin composition.
[0116] Then, the resulting composition was extruded at 300°C to pelletize.
[0117] For comparison, a comparative composition was prepared in the same manner as mentioned
above except that the above-prepared ABS resin was used instead of the rubber modified-
resin. The resulting comparative composition was pelletized in the same manner as
mentioned above.
[0118] With respect to each of the above-prepared compositions, properties were determined.
[0119] The results are shown below.
[0120] As is apparent from Table 7, the composition containing the rubber modified resin
of which the graft phase comprises two classes of copolymers is excellent in impact
strength, solvent resistance and colorability, particularly excellent in impact strength
and cololability. Whereas, the composition containing the conventionally known ABS
resin is poor in both of impact strength and colorability.
Example 13 and Comparative Example 5
[0121] A polyphenylene ether resin composition was prepared in the same manner as in Example
12 except that the polyphenylene ether was used in an amount of 40 parts by weight
instead of 50 parts by weight, that the rubber modified resin was used in an amount
of 40 parts by weight instead of 50 parts by weight and that 20 parts by weight of
a polystyrene was additionally used. The resulting com-. position was pelletized in
the same manner as in Example 12 to determine the properties of the composition.
[0122] For comparison, a comparative composition was prepared and pelletized in the same
manner as described above except that the ABS resin as prepared in Comparative Example
4 was used instead of the rubber modified resin.
[0123] The properties of each of the compositions were determined and the results are shown
below.
[0124] As is apparent from Table 8, even when polystyrene is additionally blended together
with polyphenylene ether and rubber modified resin to be used in the present invention,
the resulting composition is very excellent in impact strength, solvent resistance
and colorability.
Example 14
[0125] A polyphenylene ether resin composition was prepared in the same manner as in Example
12 except that the polyphenylene ether was used in an amount of 40 parts by weight
instead of 50 parts by weight, that the rubber modified resin was used in an amount
of 30 parts by weight instead of 50 parts by weight and that 30 parts by weight of
a copolymer containing styrene units and acrylonitrile units (acrylonitrile. moiety
content: 4% by weight) was additionally used as a diluting resin. The resulting composition
was pelletized in the same manner as in Example 12 to'determine the properties of
the composition. The results obtained are shown in Table 9.
[0126] As is apparent from the results, even when the styreneacrylonitrile copolymer having
an acrylonitrile moiety content of 4% by weight as a diluting resin is additionally
blended so that the content of rubber moiety in the composition is lowered to 12%
by weight based on the composition, the resulting composition has very high impact
strength and is also excellent in solvent resistance and colorability.
Example 15
[0127] A rubber modified resin was prepared in the same manner as described in Example 12
except that the following first and second monomer phases were used.
[0128] The first monomer phase:
[0129] The second monomer phase:
[0130] The conversion of monomers was 91%. With respect to the obtained rubber modified
resin, the grafting degree of the elastomeric.rubber phase and the AN content of each
of the graft phase and resin phase were determined. The results are as follows.
[0131] Graft phase insoluble in the mixture of acetone and methanol (7/3 by volume):
[0132] Graft phase soluble in the mixture of acetone and methanol (7/3 by volume):
[0133] A polyphenylene ether resin composition was prepared and pelletized in the same manner
as described in Example 12 except that the above-obtained rubber modified resin was
used. Properties of the obtained composition are shown below.
Example 16
[0134] A rubber modified resin was prepared in the same manner as described in Example 12
except that the following first and second monomer phases were used.
[0135] The first monomer phase:
[0136] The second monomer phase:
[0137] The conversion of monomers was 92%. With respect to the obtained rubber modified
resin, the grafting degree of the elastomeric rubber phase and the AN content of each
of the graft phase and resin phase were determined.
[0138] The results are as follows.
[0139] Graft phase insoluble in the mixture of acetone and methanol (7/3 by volume):
[0140] Graft phase soluble in the mixture of acetone and methanol (7/3 by volume):
[0141] A polyphenylene ether resin composition was prepared and pelletized in the same manner
as described in Example 12 except that the above-obtained rubber modified resin was
used. Properties of the obtained composition are shown below
Example 17
[0142] A rubber modified resin was prepared in the same manner as described in Example 12
except that the following first and second monomer phases were used.
[0143] The first monomer phase:
[0144] The second monomer phase:
[0145] The conversion of monomers was 90%.
[0146] With respect to the obtained rubber modified resin, the grafting degree of the elastomeric
rubber phase and the AN content of each of the graft phase and resin phase were determined.
The results-are shown below.
[0147] Graft phase insoluble in the mixture of acetone and methanol (7/3 by volume):
[0148] Graft phase soluble in the mixture of acetone and methanol (7/3 by volume):
[0149] A polyphenylene ether resin composition was prepared and pelletized in the same manner
as described in Example 12 except that the above-prepared rubber modified resin was
used. Properties of the resulting composition are shown below.
Example 18
[0150] A rubber modified resin was prepared in the same manner as described in Example 12
except that the amount of dodecyl mercaptan in each of the first and second monomer
phases was changed to 0.05 part by weight. The conversion of monomers was 92%.
[0151] With respect to the obtained rubber modified resin, the grafting degree of the elastomeric
phase and the AN content of each of the graft phase and resin phase were determined.
The results are as follows.
[0152] Graft phase insoluble in the mixture of acetone and methanol (7/3 by volume):
[0153] Graft phase soluble in the mixture of acetone and methanol (7/3 by volume):
[0154] A polyphenylene ether resin composition was prepared and pelletized in the same manner
as described in Example 12 except that the above-prepared rubber modified resin was
used. Properties of the composition are shown below.
[0155]